The Walk In Panels are probably the most versatile and economical way of creating a shower room

The stabilising bar enables you to choose the width aperture you want (800mm-1200mm). The Panel is completely universal and can suit existing/new shower trays or can be used in a wet room environment. The 1200mm is the perfect bath replacement panel (based on a 1700mm Bath). It can be used in conjunction with either of the 2 walk in side panel options available to create a corner enclosure. 
Click here for more details on this Walk in Front Panel